Crimp range control device



June 5 1962 H. J. PIKE, JR 3,037,260

CRIMP RANGE CONTROL DEVICE Filed May 4, 1960 2 Sheets-Sheet 1 INVENTOR, H ERBERT J. PIKE,JR.

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June 5, 1962 H. J. PIKE, JR 3,037,250

CRIMP RANGE CONTROL DEVICE Filed May 4, 1960 2 Sheets-Sheet 2 FIGZ.

INVENTOR HERBERT J. PIKE,.JR.

United States Patent 3,037,260 CRIMP RANGE CONTROL DEVICE Herbert J. Pike, Jr., Basking Ridge, N.J., assignor to Allied Chemical Corporation, New York, N.Y., a corporation of New York Filed May 4, 1969, Ser. No. 26,876 5 Claims. (Cl. 28-1) This invention relates to stufiing box crimping apparatus adapted for crimping continuous filament, tow or spun yarn. More particularly it relates to an improved stufling box crimper of the type having a loaded gate, pressing down on the material in the crimping chamber and movable in and out of the chamber to vary the size of the outlet from the crimping chamber.

Crimpers of this general type have been used commercially for the crimping of yarns for many years. However, when an attempt was made to use the prior art crimpers on some of the more newly developed yarns, it was found that the yarns crimped with the aid of these devices frequently did not take the dye evenly and consequently were considered to be of inferior quality from a commercial viewpoint. Investigation established that one of the causes of uneven dyeing or streaking of the crimped yarn was an uneven crimp frequency in the crimped yarn.

The crimp frequency, that is to say the number of crirnps per inch imparted to the yarn as it passes through a crimping device, is controlled in great part by the back pressure on the yarn as it is being fed into a confined area as well as the stiffness of the individual fibers at this time. The pressure in this confined area is due to friction against the chamber walls and constriction of the exit and can be controlled within limits by a loaded gate pressing down on the contents of the crimping chamber and movable in and out of the chamber to vary the size of the outlet from the chamber.

Crimping devices have been developed wherein a build-up in pressure within a crimping chamber over and above a predetermined limit will activate a control which will either slow down the feed rate of the yarn to the crimper or speed up the take-oif from the crimper and thereby tend to decrease the pressure therein. These devices, however, do not allow closely controlled variation of the size of the outlet from the crimper as is an important feature of the present invention to bring the crimp frequency of the crimped yarn within an acceptable range which will insure streak-free dyeing characteristics.

It is therefore an object of this invention to provide a crimper having means adapted to control the crimp frequency range of the material passed therethrough within relatively narrow limits.

It is a further object of this invention to provide a crimp range regulating device which can be adapted for use on crimpers of the prior art.

A special object is to provide a crimper adapted for use with heavy denier yarns as employed for manufacture of carpets, etc. whereby these yarns can be crimped with acceptable crimp frequency range.

In accordance with this invention it has been found that these and other objects and advantages incidental thereto can be attained by providing a stufling box crimper with a loaded gate, provided with means actuated when the loaded gate reaches a predetermined maximum open position to stop the feed rolls, and provided with means for preventing the gate from closing beyond a predetermined minimum open position, thereby holding the movement of the gate within well-defined and closely controllable limits.

The nature of the invention will be better understood by referring to the following description taken in con- 3,037,260 Patented June 5, 1962 nection with the accompanying drawings forming a part thereof in which a specific embodiment has been set forth for purposes of illustration.

In the drawings, FIGURE 1 is a perspective view partly in section of a crimping device embodying features of the invention.

FIGURE 2 is a perspective view partly in section showing the crimp frequency control device actuated by movement of the gate.

The device shown in the drawings is a stuffing box type crimper comprising a pair of nip rolls 10 positioned at one end of the stuiiing box; and a crimping chamber comprising two side walls 16 and 18 and bottom 20 rigidly held in fixed relationship with one another. The side Walls 16 and 18 extend out beyond, the front end of the nip rolls 10 which are positioned therebetween with the main portion of the crimping chamber extending out well beyond the inside nip of the feed rolls. The top of the crimping chamber is formed in two sections 22 and 24. Section 22, which abuts the periphery of the top feed roll near the inside nip, is held in rigid alignment with the side walls 16 and 18 and the bottom wall 20. These together form the receiving end of the crimping chamber. Section 24, which is referred to as the gate, is hingedly attached to section 22 by pin 25. This enables the gate 24 to move up and down within the confines of the walls 16 and 18 andto thus enlarge or restrict the size of the outlet from the crimping chamber. A rod 26 extending upward from gate 24 is adapted to hold a weight 28 thereon.

A cross bar 30 is slidably mounted across rod 26 below weight 28, extending out over the top edges of the side walls 16 and 13of the, crimping chamber. The one end of the cross bar 39 is fixedly attached to downward extending tripper bar 32. This bar 32 is positioned outside of the wall 18 and is substantially parallel therewith. As shown in FIGURE 2 of the drawings, the tripper bar 32 is in engagement with a rider wheel 34 fastened to arm 36 of a microswitch 38.

The microswitch is mounted on positioning member 40 which is carried movably on a threaded rod 52 and slidably on stationary guide bars 43 and 45 mounted between two stationary members 42 and 44. A manual control knob 46 can be used to move member 49 back and forth on guide bars 43 and 45 between stationary members 42 and 44 by means of the gears 4850 and threaded rod 52. The microswitch can be positioned so as to supply or turn off the power driving the nip rolls 10 at a predetermined point in the arc travelled by the microswitch tripper bar 32 as the tripper bar moves along with the gate 24. I I Cylinder 33 is a'stationary cylinder over which the yarn passes, to prevent loops, etc., on its way to the takeup device (not shown).

In operation, the crimped yarn is removed from the crimping chamber at a constant speed slightly lower than that at which the yarn is fed into the chamber. This gradually causes the amount of yarn in the chamber to build up whereby the gate 24 is raised and the tripper bar 32 is moved in an are away from the arm 36, until the microswitch 38 is deactivated, shutting oif the power to the feed rolls 10. Continued removal of the crimped yarn at constant speed from the crimping chamber causes the gate 24 to descend until the tripper bar '32 reactivates the microswitch thereby supplying power to the feed rolls 10 whereupon the gate normally begins to rise immediately and the cycle is again repeated. The speed of the feed rolls should be adjusted so as to give a maximum on period and a minimum off period during the operation, whereby it is possible when using my apparatus, to hold the crimp characteristics of the yarn within a narrow range.

The downward drop of the gate 24 in the exit end of the crimping chamber is limited by the cross bar 30 mounted across the control rod 26 and extending beyond the sides of the crimping chamber. Although desirably the gate begins to rise as soon as the feed rolls are restarted by the microswitch, on occasion, the feed fails immediately to catch up with the withdrawal of yarn, I have found. The result is a continued descent of the gate. Any descent of the gate substantially below the position parallel to the bottom of the chamber quickly increases the pressure against the yarn in the chamber and results in a sharp rise in crimp frequency in the incoming yarn. Such irregularity is prevented by my stop bar which prevents descent of the gate below a predetermined minimum open position.

In the crimper illustrated, the gate movement at the outlet from the crimping chamber is limited to maintain a height of the outlet from about 1%" to 1 that is to say the maximum gate movement between stop bar 30 and the top of the stuffing box at the point when the yarn pressure deactivates the microswith to turn ofi the feed rolls, is about The maximum gate movement can be adjusted by turning the knurled knob 46 which by means of gears 48 and 50 and screw thread 52, causes the movable positioning member 40 which carries the microswitch '38 to be moved toward or away from the tripper bar 32.

The eifect of the maximum gate movement (as fixed by the stop bar and microswitch) during the crimping operation on the crimp characteristics of a 2100 denier, filament, /2 Z-twist continuous drawn nylon-6 yarn passed through the stuffing box can be seen from the example for which data are tabulated below:

EFFECT OF GATE MOVEMENT ON CRIMP CHARACTERISTICS Test Conditions and Results [Yarn feed rate=685 [t./rnin.; take-up rate of crimped yarn= 540 it./min.]

Maximum Gate Movement, inches.

Gate Stop Distance (from bottom of chamber), inches 1% 1% 1% 1% Avg. Crimp Frequency,

crimps/inch U 5 1 54 it: /is

ited

Range Crimp Frequency,

crimps/inch crimp frequency range from 13-20 crimps per inch, whereas maximum gate movement limited to inch maintained the crimp frequency between 11 and 16 crimps per inch.

Although certain preferred embodiments of the inven" tion have been disclosed for purpose of illustration, it will be evident that various changes and modifications may be made therein without departing from the scope and spirit of the invention. For example, the switch can be connected to the take-up drive instead of the feed roll drive, to stop the take-up rolls at the low position of the loaded gate; and a stop will then be provided to limit the upward movement of the gate to a small range; moreover, the crimping chamber need not be horizontal as in the drawings, and the gate can be positioned otherwise than at the top of the chamber (being then suitably loaded by spring or pnuematic pressure).

I claim:

1. Stufiing box crimping apparatus comprising a crimping chamber; a pair of feed rolls positioned to feed filamentary material continuously through one end of said chamber; means for withdrawing crimped filament from the opposite end of said chamber; a loaded gate pressing down on the material in said chamber and movable in and out of said chamber to vary the size of the outlet from the chamber; means actuated when the gate reaches a maximum open position to stop said feed rolls; and means preventing movement of said gate beyond a predetermined minimum open position, thereby holding the movement of said gate within controlled limits.

2. Apparatus as set forth in claim 1 wherein the gate, at its maximum open position, deactivates a switch supplying the power for driving the feed rolls thereby stopping the feed of said filament to said crimping chamber and wherein a stop is provided to prevent the movement of said gate beyond the minimum open position.

3. Apparatus as set forth in claim 2 wherein the maximum gate movement is set at not more than inch by setting the position in the travel of the gate at which the switch is deactivated.

4. Apparatus as set forth in claim 2 wherein the stop is a cross bar which comes to rest on the crimping chamber walls and which is connected to said gate at an adjustable distance therefrom.

5. Apparatus as set forth in claim 4 wherein a tripper bar is adaptably mounted on the stop bar for connecting and breaking contact with a switch during movement of said gate to start and stop the supply of power for driving said feed rolls.

References Cited in the file of this patent UNITED STATES PATENTS 

